: Diffuse supernova neutrino background (DSNB) as the integrated flux from all past core-collapse supernova explosions, if detected, would be a probe to explore the supernova mechanism as well as stellar evolution. In this talk, I will give a short review of theoretical and experimental status of the DSNB studies and then present the latest search result from Super-Kamiokande. I will also mention the reach of future experiments and recent phenomenological works.